The field of the present invention relates generally to flexible hinges, and more particularly to such hinges made of a polymer material.
It known in the art to use polymer material or flexible plastic material for providing a flexible hinge or web connected between rigid and unflexible material. For example, in the power lawn mower industry industrial safety standards have demanded that shields known as either drag shields, safety shields or trail shields be connected across the rear portion of the mower to prevent stones and other debris from being thrown up at the operator as they walk behind power mower. As described in greater detail below, one known type of trail shield includes a web of flexible Poly Vinyl Chloride (PVC) material connected between a rigid pivotal structure or tube like element of vinyl material, for connection to the rear deck of a walk behind power mower, with the other end of the web being secured to a relatively large diameter tubular structure or curved end structure for gliding along and following the contours of a lawn being mowed. Typically the PVC flexible web is laminated to the tubular attachment member, and the large diameter tubular curved ground follower rigid vinyl structure. Because of the dissimilarity of the materials, it has been found that a delamination problem exists during use. Due to the flexing back and forth of the web and the attached rigid members, the bonds therebetween tend to break away, ultimately causing premature failure of the safety device, in this example, a drag shield. However, this problem can occur for any applications utilizing a flexible web of one material connected between rigid members of another material.
With the problems of the prior art in mind, the present invention includes two opposing and spaced apart rigid members of a first polymer material connected together by a centrally located web therebetween of the same material, with the web being a continuous structure emanating from each one of the opposing rigid members, whereby the web is made thin enough to permitted it to be flexible. The rigid members including the web are in one embodiment of the invention fabricated from a common rigid plastic material. A flexible plastic material is laminated to the interconnecting rigid plastic web material on opposing sides thereof, for strengthening the web, and improving its impact resistance.